Produced fluids including hydrocarbon gases and oil often contain unacceptable levels of heavy metals such as mercury. Presence of the mercury in the fluids can limit options for materials used in fluid handling facilities due to corrosiveness and can cause problems with downstream processing units as well as health and environmental issues if released as waste. Common approaches to remove mercury in such produced fluids utilize treatments for the fluids once the fluids are recovered from subterranean reservoirs and brought to a surface of the earth.
Surface systems often employ mercury treatment vessels packed with sorbent for the mercury. In operation, the fluid passes through the vessels and contacts the sorbent for removal of the mercury. Various compositions provide the sorbent loaded into the treatment vessels.
Problems associated with past techniques for mercury removal include corrosion hazards associated with materials, such as aluminum used to make heat exchangers, that the fluid contacts before exiting the mercury treatment vessels. The mercury located at the surface also presents safety risks from occupational exposure. Further, capital costs of the treatment vessels and operating costs with hazardous waste shipment and disposal of the mercury and contaminated spent equipment make prior approaches for the mercury removal at the surface expensive.
Therefore, a need exists for methods and systems suitable for treatment of fluids to remove heavy metals.